What is small fibre neuropathy?

Small fibre peripheral neuropathy is a type of peripheral neuropathy that occurs from damage to the small unmyelinated peripheral nerve fibres. These fibres, categorised as C fibres and small Aδ fibres, are present in the skin, peripheral nerves, and organs.

The role of Aδ and C fibres is to carry the sensation of temperature and pain as well as to help control the function of the sweat glands, gastrointestinal organs, blood vessels and heart.

The incidence and prevalence is not known but the number of patients with the small fibre neuropathy has been increasing as the awareness of the condition has risen in the world.

Symptoms of small fibre neuropathy

Small fibre neuropathy typically causes a painful and burning sensation, often in the feet, but also in other parts of the body including the arms, face and trunk.

The pain is usually constant but can vary throughout the day and it can be worse during rest or at night. The patients are sensitive to touch and may get pain from bed sheets touching their feet.

Patients may also report transient electric shock-like pain lasting for seconds but many times during the day. Cramps can also occur.

Patients also report:

• light-headedness
• postural hypotension
• presyncope
• syncope
• abnormal sweating
• gastrointestinal and sexual dysfunction

Patients with small fibre neuropathy may be misdiagnosed as having a plantar fasciitis, fibromyalgia or psychosomatic syndrome.

Examination and Diagnosis

Neurological examination of patients with small fibre neuropathy is often normal although some patients may have decreased pinprick or temperature sensation or hyperalgesia and allodynia.

The skin can be dry, cracked or shiny in the affected areas. A postural blood pressure drop with resting tachycardia may be seen in patients who have autonomic impairment.

Nerve conduction studies in small fibre neuropathy are normal but they should be done to establish whether the patient has a large fibre neuropathy as this may help with the diagnostic process.

The London Clinic offers treatment for small fibre neuropathy, involving a skin biopsy test.